Methanesulfonic acid (MSA) has been proven as a scale remover and, more recently, as a stand-alone stimulation fluid in carbonate acidizing. MSA is a strong alkyl sulfonic acid having a pK value of -1.9, and it dissolves carbonate and oxides with its calcium water-soluble salts. Although the acid has many promising results for acidizing, little is known in relation to its detailed kinetics. This study aims to understand the reaction profile of MSA to provide relevant information to scientists and engineers to design acidizing jobs with this improved fluid.
The dissolution of calcite in MSA was studied with the aid of a rotating disk system at 1000 psig in the temperature range 73-250°F. As a result of this study dissolution rate parameters for this system are reported for the first time. Details of the approach for this study include using marble disks of 1.5-in. diameter and 0.7-in. thickness. The dissolution rate was found by measuring the calcium concentration in the effluent as a function of time using inductively coupled plasma (ICP). The effects of MSA concentrations (5 to 20 wt%), disk rotational speeds (100 to 1500 rpm), and temperatures on the rate of dissolution were also investigated.
Experimental results showed that, within the range of temperatures tested, the dissolution rate of MSA with calcite was mass-transfer limited even at high disk rotation speeds. The diffusion coefficient of a 5 wt% MSA fluid at 150°F was found to be 5.29 × 10-5 cm2/s and at 250°F diffusion coefficient was found to be 3.03 × 10-4 cm2/s. The acid diffusivity increased with increasing system temperature.
Determination of the dissolution rate of MSA will increase the understanding of its performance as a stand-alone stimulation fluid. Its high acidity, high solubility of its calcium salts, and good thermal stability, along with its low corrosivity and readily biodegradable composition makes this acid an attractive alternative to HC1 in designing high temperature acidizing applications.
MSA甲基磺酸是一种可以自然生物降解的有机酸，具有非常强的酸性，pKA= -1.9，MSA甲基磺酸是一种高效的酸性产品；同时又是低腐蚀性产品，不会对材料表面造成非常严重的腐蚀；同时也是无磷环保型产品，自身身会进行生物降解；比起传统的挥发性酸来说，MSA是低挥发性、低毒的产品。
高钙盐溶解度，耐高温，低腐蚀，可生物降解，在高温井是替代盐酸很好的选择。
